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                    第三章：基础组件
            
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                    3.1：Widget简介
            
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                    3.5：图片和Icon
            
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                    3.6：单选框和复选框
            
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                    第四章：布局类组件
            
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                    4.2：线性布局（Row、Column）
            
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                    4.3：弹性布局（Flex）
            
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                    4.4：流式布局（Wrap、Flow）
            
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                    4.5：层叠布局（Stack、Positioned）
            
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                    4.6：对齐与相对定位（Align）
            
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                    第五章：容器类组件
            
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                    5.1：填充（Padding）
            
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                    5.2：尺寸限制类容器（ConstrainedBox等）
            
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                    5.3：装饰容器（DecoratedBox）
            
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                    5.4：变换（Transform）
            
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                    5.5：Container容器
            
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                    5.6：Scaffold、TabBar、底部导航
            
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                    5.7：剪裁（Clip）
            
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                    第六章：可滚动组件
            
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                    6.1：可滚动组件简介
            
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                    6.2：SingleChildScrollView
            
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                    6.3：ListView
            
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                    6.4：GridView
            
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                    6.5：CustomScrollView
            
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                    6.6：滚动监听及控制（ScrollController）
            
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                    第七章：功能型组件
            
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                    7.1：导航返回拦截（WillPopScope）
            
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                    7.2：数据共享（InheritedWidget）
            
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                    7.3： 跨组件状态共享（Provider）
            
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                    7.4：颜色和主题（Theme）
            
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                    7.5：异步UI更新（FutureBuilder、StreamBuilder）
            
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                    7.6：对话框详解
            
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        <li class="header">进阶篇</li>
        
        
    
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                    第八章：事件处理与通知
            
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                    8.1：原始指针事件处理
            
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                    8.2：手势识别
            
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                    8.3：全局事件总线
            
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                    8.4：通知(Notification)
            
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                    第九章：动画
            
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                    9.1：Flutter动画简介
            
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                    9.2：动画结构
            
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                    9.3：自定义路由过渡动画
            
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                    9.4：Hero动画
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.2.5" data-path="../chapter9/stagger_animation.html">
            
                <a href="../chapter9/stagger_animation.html">
            
                    
                    9.5：交织动画
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.2.6" data-path="../chapter9/animated_switcher.html">
            
                <a href="../chapter9/animated_switcher.html">
            
                    
                    9.6：通用“动画切换”组件（AnimatedSwitcher）
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.2.7" data-path="../chapter9/animated_widgets.html">
            
                <a href="../chapter9/animated_widgets.html">
            
                    
                    9.7：动画过渡组件
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.3" data-path="./">
            
                <a href="./">
            
                    
                    第十章：自定义组件
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.3.1" data-path="intro.html">
            
                <a href="intro.html">
            
                    
                    10.1：自定义组件方法简介
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.3.2" data-path="combine.html">
            
                <a href="combine.html">
            
                    
                    10.2：组合现有组件
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.3.3" data-path="turn_box.html">
            
                <a href="turn_box.html">
            
                    
                    10.3：组合实例：TurnBox
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.3.4" data-path="custom_paint.html">
            
                <a href="custom_paint.html">
            
                    
                    10.4：自绘组件（CustomPaint与Canvas）
            
                </a>
            

            
        </li>
    
        <li class="chapter active" data-level="3.3.5" data-path="gradient_circular_progress_demo.html">
            
                <a href="gradient_circular_progress_demo.html">
            
                    
                    10.5：自绘实例：圆形渐变进度条(自绘)
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.4" data-path="../chapter11/">
            
                <a href="../chapter11/">
            
                    
                    第十一章：文件操作与网络请求
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.4.1" data-path="../chapter11/file_operation.html">
            
                <a href="../chapter11/file_operation.html">
            
                    
                    11.1：文件操作
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.2" data-path="../chapter11/http.html">
            
                <a href="../chapter11/http.html">
            
                    
                    11.2：Http请求-HttpClient
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.3" data-path="../chapter11/dio.html">
            
                <a href="../chapter11/dio.html">
            
                    
                    11.3：Http请求-Dio package
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.4" data-path="../chapter11/download_with_chunks.html">
            
                <a href="../chapter11/download_with_chunks.html">
            
                    
                    11.4：实例：Http分块下载
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.5" data-path="../chapter11/websocket.html">
            
                <a href="../chapter11/websocket.html">
            
                    
                    11.5：WebSocket
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.6" data-path="../chapter11/socket.html">
            
                <a href="../chapter11/socket.html">
            
                    
                    11.6：使用Socket API
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.7" data-path="../chapter11/json_model.html">
            
                <a href="../chapter11/json_model.html">
            
                    
                    11.7：Json转Dart Model类
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.5" data-path="../chapter12/">
            
                <a href="../chapter12/">
            
                    
                    第十二章：包与插件
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.5.1" data-path="../chapter12/develop_package.html">
            
                <a href="../chapter12/develop_package.html">
            
                    
                    12.1：开发package
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.5.2" data-path="../chapter12/platform-channel.html">
            
                <a href="../chapter12/platform-channel.html">
            
                    
                    12.2：平台通道简介
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.5.3" data-path="../chapter12/develop_plugin.html">
            
                <a href="../chapter12/develop_plugin.html">
            
                    
                    12.3：开发Flutter插件
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.5.4" data-path="../chapter12/android_implement.html">
            
                <a href="../chapter12/android_implement.html">
            
                    
                    12.4：插件开发：实现Android端API
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.5.5" data-path="../chapter12/ios_implement.html">
            
                <a href="../chapter12/ios_implement.html">
            
                    
                    12.5：插件开发：实现IOS端API
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.5.6" data-path="../chapter12/texture_platformview.html">
            
                <a href="../chapter12/texture_platformview.html">
            
                    
                    12.6：Texture和PlatformView
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.6" data-path="../chapter13/">
            
                <a href="../chapter13/">
            
                    
                    第十三章：国际化
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.6.1" data-path="../chapter13/multi_languages_support.html">
            
                <a href="../chapter13/multi_languages_support.html">
            
                    
                    13.1：让App支持多语言
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.6.2" data-path="../chapter13/locallization_implement.html">
            
                <a href="../chapter13/locallization_implement.html">
            
                    
                    13.2：实现Localizations
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.6.3" data-path="../chapter13/intl.html">
            
                <a href="../chapter13/intl.html">
            
                    
                    13.3：使用Intl包
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.6.4" data-path="../chapter13/faq.html">
            
                <a href="../chapter13/faq.html">
            
                    
                    13.4：国际化常见问题
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.7" data-path="../chapter14/">
            
                <a href="../chapter14/">
            
                    
                    第十四章：Flutter核心原理
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.7.1" data-path="../chapter14/flutter_ui_system.html">
            
                <a href="../chapter14/flutter_ui_system.html">
            
                    
                    14.1：Flutter UI系统
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.7.2" data-path="../chapter14/element_buildcontext.html">
            
                <a href="../chapter14/element_buildcontext.html">
            
                    
                    14.2：Element和BuildContext
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.7.3" data-path="../chapter14/render_object.html">
            
                <a href="../chapter14/render_object.html">
            
                    
                    14.3：RenderObject与RenderBox
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.7.4" data-path="../chapter14/flutter_app_startup.html">
            
                <a href="../chapter14/flutter_app_startup.html">
            
                    
                    14.4：Flutter从启动到显示
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.7.5" data-path="../chapter14/image_and_cache.html">
            
                <a href="../chapter14/image_and_cache.html">
            
                    
                    14.5：Flutter图片加载与缓存
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    

    
        
        <li class="header">实例篇</li>
        
        
    
        <li class="chapter " data-level="4.1" data-path="../chapter15/intro.html">
            
                <a href="../chapter15/intro.html">
            
                    
                    第十五章：一个完整的Flutter应用
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="4.1.1" data-path="../chapter15/intro.html">
            
                <a href="../chapter15/intro.html">
            
                    
                    15.1：应用简介
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.2" data-path="../chapter15/code_structure.html">
            
                <a href="../chapter15/code_structure.html">
            
                    
                    15.2：APP代码结构
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.3" data-path="../chapter15/models.html">
            
                <a href="../chapter15/models.html">
            
                    
                    15.3：Model类定义
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.4" data-path="../chapter15/globals.html">
            
                <a href="../chapter15/globals.html">
            
                    
                    15.4：全局变量及共享状态
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.5" data-path="../chapter15/network.html">
            
                <a href="../chapter15/network.html">
            
                    
                    15.5：网络请求封装
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.6" data-path="../chapter15/entry.html">
            
                <a href="../chapter15/entry.html">
            
                    
                    15.6：App入口及首页
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.7" data-path="../chapter15/login_page.html">
            
                <a href="../chapter15/login_page.html">
            
                    
                    15.7：登录页
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.8" data-path="../chapter15/language_and_theme_setting.html">
            
                <a href="../chapter15/language_and_theme_setting.html">
            
                    
                    15.8：多语言和多主题
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    

    

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<pre class="language-"><code class="lang-dart"><span class="token keyword">import</span> <span class="token string">&apos;dart:math&apos;</span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token string">&apos;package:flutter/material.dart&apos;</span><span class="token punctuation">;</span>

<span class="token keyword">class</span> <span class="token class-name">GradientCircularProgressIndicator</span> <span class="token keyword">extends</span> <span class="token class-name">StatelessWidget</span> <span class="token punctuation">{</span>
  <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>strokeWidth <span class="token operator">=</span> <span class="token number">2.0</span><span class="token punctuation">,</span>
    <span class="token metadata symbol">@required</span> <span class="token keyword">this</span><span class="token punctuation">.</span>radius<span class="token punctuation">,</span>
    <span class="token metadata symbol">@required</span> <span class="token keyword">this</span><span class="token punctuation">.</span>colors<span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>stops<span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>strokeCapRound <span class="token operator">=</span> <span class="token boolean">false</span><span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>backgroundColor <span class="token operator">=</span> <span class="token keyword">const</span> <span class="token function">Color</span><span class="token punctuation">(</span><span class="token number">0xFFEEEEEE</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>totalAngle <span class="token operator">=</span> <span class="token number">2</span> <span class="token operator">*</span> pi<span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>value
  <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

  <span class="token comment">///&#x7C97;&#x7EC6;</span>
  <span class="token keyword">final</span> double strokeWidth<span class="token punctuation">;</span>

  <span class="token comment">/// &#x5706;&#x7684;&#x534A;&#x5F84;</span>
  <span class="token keyword">final</span> double radius<span class="token punctuation">;</span>

  <span class="token comment">///&#x4E24;&#x7AEF;&#x662F;&#x5426;&#x4E3A;&#x5706;&#x89D2;</span>
  <span class="token keyword">final</span> bool strokeCapRound<span class="token punctuation">;</span>

  <span class="token comment">/// &#x5F53;&#x524D;&#x8FDB;&#x5EA6;&#xFF0C;&#x53D6;&#x503C;&#x8303;&#x56F4; [0.0-1.0]</span>
  <span class="token keyword">final</span> double value<span class="token punctuation">;</span>

  <span class="token comment">/// &#x8FDB;&#x5EA6;&#x6761;&#x80CC;&#x666F;&#x8272;</span>
  <span class="token keyword">final</span> Color backgroundColor<span class="token punctuation">;</span>

  <span class="token comment">/// &#x8FDB;&#x5EA6;&#x6761;&#x7684;&#x603B;&#x5F27;&#x5EA6;&#xFF0C;2*PI&#x4E3A;&#x6574;&#x5706;&#xFF0C;&#x5C0F;&#x4E8E;2*PI&#x5219;&#x4E0D;&#x662F;&#x6574;&#x5706;</span>
  <span class="token keyword">final</span> double totalAngle<span class="token punctuation">;</span>

  <span class="token comment">/// &#x6E10;&#x53D8;&#x8272;&#x6570;&#x7EC4;</span>
  <span class="token keyword">final</span> List<span class="token operator">&lt;</span>Color<span class="token operator">&gt;</span> colors<span class="token punctuation">;</span>

  <span class="token comment">/// &#x6E10;&#x53D8;&#x8272;&#x7684;&#x7EC8;&#x6B62;&#x70B9;&#xFF0C;&#x5BF9;&#x5E94;colors&#x5C5E;&#x6027;</span>
  <span class="token keyword">final</span> List<span class="token operator">&lt;</span>double<span class="token operator">&gt;</span> stops<span class="token punctuation">;</span>

  <span class="token metadata symbol">@override</span>
  Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    double _offset <span class="token operator">=</span> <span class="token number">.0</span><span class="token punctuation">;</span>
    <span class="token comment">// &#x5982;&#x679C;&#x4E24;&#x7AEF;&#x4E3A;&#x5706;&#x89D2;&#xFF0C;&#x5219;&#x9700;&#x8981;&#x5BF9;&#x8D77;&#x59CB;&#x4F4D;&#x7F6E;&#x8FDB;&#x884C;&#x8C03;&#x6574;&#xFF0C;&#x5426;&#x5219;&#x5706;&#x89D2;&#x90E8;&#x5206;&#x4F1A;&#x504F;&#x79BB;&#x8D77;&#x59CB;&#x4F4D;&#x7F6E;</span>
    <span class="token comment">// &#x4E0B;&#x9762;&#x8C03;&#x6574;&#x7684;&#x89D2;&#x5EA6;&#x7684;&#x8BA1;&#x7B97;&#x516C;&#x5F0F;&#x662F;&#x901A;&#x8FC7;&#x6570;&#x5B66;&#x51E0;&#x4F55;&#x77E5;&#x8BC6;&#x5F97;&#x51FA;&#xFF0C;&#x8BFB;&#x8005;&#x6709;&#x5174;&#x8DA3;&#x53EF;&#x4EE5;&#x7814;&#x7A76;&#x4E00;&#x4E0B;&#x4E3A;&#x4EC0;&#x4E48;&#x662F;&#x8FD9;&#x6837;  </span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>strokeCapRound<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      _offset <span class="token operator">=</span> <span class="token function">asin</span><span class="token punctuation">(</span>strokeWidth <span class="token operator">/</span> <span class="token punctuation">(</span>radius <span class="token operator">*</span> <span class="token number">2</span> <span class="token operator">-</span> strokeWidth<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
    <span class="token keyword">var</span> _colors <span class="token operator">=</span> colors<span class="token punctuation">;</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>_colors <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      Color color <span class="token operator">=</span> Theme
          <span class="token punctuation">.</span><span class="token function">of</span><span class="token punctuation">(</span>context<span class="token punctuation">)</span>
          <span class="token punctuation">.</span>accentColor<span class="token punctuation">;</span>
      _colors <span class="token operator">=</span> <span class="token punctuation">[</span>color<span class="token punctuation">,</span> color<span class="token punctuation">]</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
    <span class="token keyword">return</span> Transform<span class="token punctuation">.</span><span class="token function">rotate</span><span class="token punctuation">(</span>
      angle<span class="token punctuation">:</span> <span class="token operator">-</span>pi <span class="token operator">/</span> <span class="token number">2.0</span> <span class="token operator">-</span> _offset<span class="token punctuation">,</span> 
      child<span class="token punctuation">:</span> <span class="token function">CustomPaint</span><span class="token punctuation">(</span>
          size<span class="token punctuation">:</span> Size<span class="token punctuation">.</span><span class="token function">fromRadius</span><span class="token punctuation">(</span>radius<span class="token punctuation">)</span><span class="token punctuation">,</span>
          painter<span class="token punctuation">:</span> <span class="token function">_GradientCircularProgressPainter</span><span class="token punctuation">(</span>
            strokeWidth<span class="token punctuation">:</span> strokeWidth<span class="token punctuation">,</span>
            strokeCapRound<span class="token punctuation">:</span> strokeCapRound<span class="token punctuation">,</span>
            backgroundColor<span class="token punctuation">:</span> backgroundColor<span class="token punctuation">,</span>
            value<span class="token punctuation">:</span> value<span class="token punctuation">,</span>
            total<span class="token punctuation">:</span> totalAngle<span class="token punctuation">,</span>
            radius<span class="token punctuation">:</span> radius<span class="token punctuation">,</span>
            colors<span class="token punctuation">:</span> _colors<span class="token punctuation">,</span>
          <span class="token punctuation">)</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

<span class="token comment">//&#x5B9E;&#x73B0;&#x753B;&#x7B14;</span>
<span class="token keyword">class</span> <span class="token class-name">_GradientCircularProgressPainter</span> <span class="token keyword">extends</span> <span class="token class-name">CustomPainter</span> <span class="token punctuation">{</span>
  <span class="token function">_GradientCircularProgressPainter</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>strokeWidth<span class="token punctuation">:</span> <span class="token number">10.0</span><span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>strokeCapRound<span class="token punctuation">:</span> <span class="token boolean">false</span><span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>backgroundColor <span class="token operator">=</span> <span class="token keyword">const</span> <span class="token function">Color</span><span class="token punctuation">(</span><span class="token number">0xFFEEEEEE</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>radius<span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>total <span class="token operator">=</span> <span class="token number">2</span> <span class="token operator">*</span> pi<span class="token punctuation">,</span>
    <span class="token metadata symbol">@required</span> <span class="token keyword">this</span><span class="token punctuation">.</span>colors<span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>stops<span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>value
  <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

  <span class="token keyword">final</span> double strokeWidth<span class="token punctuation">;</span>
  <span class="token keyword">final</span> bool strokeCapRound<span class="token punctuation">;</span>
  <span class="token keyword">final</span> double value<span class="token punctuation">;</span>
  <span class="token keyword">final</span> Color backgroundColor<span class="token punctuation">;</span>
  <span class="token keyword">final</span> List<span class="token operator">&lt;</span>Color<span class="token operator">&gt;</span> colors<span class="token punctuation">;</span>
  <span class="token keyword">final</span> double total<span class="token punctuation">;</span>
  <span class="token keyword">final</span> double radius<span class="token punctuation">;</span>
  <span class="token keyword">final</span> List<span class="token operator">&lt;</span>double<span class="token operator">&gt;</span> stops<span class="token punctuation">;</span>

  <span class="token metadata symbol">@override</span>
  <span class="token keyword">void</span> <span class="token function">paint</span><span class="token punctuation">(</span>Canvas canvas<span class="token punctuation">,</span> Size size<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>radius <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      size <span class="token operator">=</span> Size<span class="token punctuation">.</span><span class="token function">fromRadius</span><span class="token punctuation">(</span>radius<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
    double _offset <span class="token operator">=</span> strokeWidth <span class="token operator">/</span> <span class="token number">2.0</span><span class="token punctuation">;</span>
    double _value <span class="token operator">=</span> <span class="token punctuation">(</span>value <span class="token operator">?</span><span class="token operator">?</span> <span class="token number">.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    _value <span class="token operator">=</span> _value<span class="token punctuation">.</span><span class="token function">clamp</span><span class="token punctuation">(</span><span class="token number">.0</span><span class="token punctuation">,</span> <span class="token number">1.0</span><span class="token punctuation">)</span> <span class="token operator">*</span> total<span class="token punctuation">;</span>
    double _start <span class="token operator">=</span> <span class="token number">.0</span><span class="token punctuation">;</span>

    <span class="token keyword">if</span> <span class="token punctuation">(</span>strokeCapRound<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      _start <span class="token operator">=</span> <span class="token function">asin</span><span class="token punctuation">(</span>strokeWidth<span class="token operator">/</span> <span class="token punctuation">(</span>size<span class="token punctuation">.</span>width <span class="token operator">-</span> strokeWidth<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    Rect rect <span class="token operator">=</span> <span class="token function">Offset</span><span class="token punctuation">(</span>_offset<span class="token punctuation">,</span> _offset<span class="token punctuation">)</span> <span class="token operator">&amp;</span> <span class="token function">Size</span><span class="token punctuation">(</span>
        size<span class="token punctuation">.</span>width <span class="token operator">-</span> strokeWidth<span class="token punctuation">,</span>
        size<span class="token punctuation">.</span>height <span class="token operator">-</span> strokeWidth
    <span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token keyword">var</span> paint <span class="token operator">=</span> <span class="token function">Paint</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
      <span class="token punctuation">.</span><span class="token punctuation">.</span>strokeCap <span class="token operator">=</span> strokeCapRound <span class="token operator">?</span> StrokeCap<span class="token punctuation">.</span>round <span class="token punctuation">:</span> StrokeCap<span class="token punctuation">.</span>butt
      <span class="token punctuation">.</span><span class="token punctuation">.</span>style <span class="token operator">=</span> PaintingStyle<span class="token punctuation">.</span>stroke
      <span class="token punctuation">.</span><span class="token punctuation">.</span>isAntiAlias <span class="token operator">=</span> <span class="token boolean">true</span>
      <span class="token punctuation">.</span><span class="token punctuation">.</span>strokeWidth <span class="token operator">=</span> strokeWidth<span class="token punctuation">;</span>

    <span class="token comment">// &#x5148;&#x753B;&#x80CC;&#x666F;</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>backgroundColor <span class="token operator">!=</span> Colors<span class="token punctuation">.</span>transparent<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      paint<span class="token punctuation">.</span>color <span class="token operator">=</span> backgroundColor<span class="token punctuation">;</span>
      canvas<span class="token punctuation">.</span><span class="token function">drawArc</span><span class="token punctuation">(</span>
          rect<span class="token punctuation">,</span>
          _start<span class="token punctuation">,</span>
          total<span class="token punctuation">,</span>
          <span class="token boolean">false</span><span class="token punctuation">,</span>
          paint
      <span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token comment">// &#x518D;&#x753B;&#x524D;&#x666F;&#xFF0C;&#x5E94;&#x7528;&#x6E10;&#x53D8;</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>_value <span class="token operator">&gt;</span> <span class="token number">0</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      paint<span class="token punctuation">.</span>shader <span class="token operator">=</span> <span class="token function">SweepGradient</span><span class="token punctuation">(</span>
        startAngle<span class="token punctuation">:</span> <span class="token number">0.0</span><span class="token punctuation">,</span>
        endAngle<span class="token punctuation">:</span> _value<span class="token punctuation">,</span>
        colors<span class="token punctuation">:</span> colors<span class="token punctuation">,</span>
        stops<span class="token punctuation">:</span> stops<span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">createShader</span><span class="token punctuation">(</span>rect<span class="token punctuation">)</span><span class="token punctuation">;</span>

      canvas<span class="token punctuation">.</span><span class="token function">drawArc</span><span class="token punctuation">(</span>
          rect<span class="token punctuation">,</span>
          _start<span class="token punctuation">,</span>
          _value<span class="token punctuation">,</span>
          <span class="token boolean">false</span><span class="token punctuation">,</span>
          paint
      <span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span>

  <span class="token metadata symbol">@override</span>
  bool <span class="token function">shouldRepaint</span><span class="token punctuation">(</span>CustomPainter oldDelegate<span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">&gt;</span> <span class="token boolean">true</span><span class="token punctuation">;</span>

<span class="token punctuation">}</span>
</code></pre>
<p>&#x4E0B;&#x9762;&#x6211;&#x4EEC;&#x6765;&#x6D4B;&#x8BD5;&#x4E00;&#x4E0B;&#xFF0C;&#x4E3A;&#x4E86;&#x5C3D;&#x53EF;&#x80FD;&#x591A;&#x7684;&#x5C55;&#x793A;<code>GradientCircularProgressIndicator</code>&#x7684;&#x4E0D;&#x540C;&#x5916;&#x89C2;&#x548C;&#x7528;&#x9014;&#xFF0C;&#x8FD9;&#x4E2A;&#x793A;&#x4F8B;&#x4EE3;&#x7801;&#x4F1A;&#x6BD4;&#x8F83;&#x957F;&#xFF0C;&#x5E76;&#x4E14;&#x6DFB;&#x52A0;&#x4E86;&#x52A8;&#x753B;&#xFF0C;&#x5EFA;&#x8BAE;&#x8BFB;&#x8005;&#x5C06;&#x6B64;&#x793A;&#x4F8B;&#x8FD0;&#x884C;&#x8D77;&#x6765;&#x89C2;&#x770B;&#x5B9E;&#x9645;&#x6548;&#x679C;&#xFF0C;&#x6211;&#x4EEC;&#x5148;&#x770B;&#x770B;&#x5176;&#x4E2D;&#x7684;&#x4E00;&#x5E27;&#x52A8;&#x753B;&#x7684;&#x622A;&#x56FE;&#xFF1A;</p>
<p><img src="https://pcdn.flutterchina.club/imgs/gradient_circular_progress.png" alt="gradient_circular_progress"></p>
<p>&#x793A;&#x4F8B;&#x4EE3;&#x7801;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">import</span> <span class="token string">&apos;dart:math&apos;</span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token string">&apos;package:flutter/material.dart&apos;</span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token string">&apos;../widgets/index.dart&apos;</span><span class="token punctuation">;</span>

<span class="token keyword">class</span> <span class="token class-name">GradientCircularProgressRoute</span> <span class="token keyword">extends</span> <span class="token class-name">StatefulWidget</span> <span class="token punctuation">{</span>
  <span class="token metadata symbol">@override</span>
  GradientCircularProgressRouteState <span class="token function">createState</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">GradientCircularProgressRouteState</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

<span class="token keyword">class</span> <span class="token class-name">GradientCircularProgressRouteState</span>
    <span class="token keyword">extends</span> <span class="token class-name">State</span><span class="token operator">&lt;</span>GradientCircularProgressRoute<span class="token operator">&gt;</span> <span class="token keyword">with</span> TickerProviderStateMixin <span class="token punctuation">{</span>
  AnimationController _animationController<span class="token punctuation">;</span>

  <span class="token metadata symbol">@override</span>
  <span class="token keyword">void</span> <span class="token function">initState</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">super</span><span class="token punctuation">.</span><span class="token function">initState</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    _animationController <span class="token operator">=</span>
        <span class="token keyword">new</span> <span class="token class-name">AnimationController</span><span class="token punctuation">(</span>vsync<span class="token punctuation">:</span> <span class="token keyword">this</span><span class="token punctuation">,</span> duration<span class="token punctuation">:</span> <span class="token function">Duration</span><span class="token punctuation">(</span>seconds<span class="token punctuation">:</span> <span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    bool isForward <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
    _animationController<span class="token punctuation">.</span><span class="token function">addStatusListener</span><span class="token punctuation">(</span><span class="token punctuation">(</span>status<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token keyword">if</span> <span class="token punctuation">(</span>status <span class="token operator">==</span> AnimationStatus<span class="token punctuation">.</span>forward<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        isForward <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
      <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>status <span class="token operator">==</span> AnimationStatus<span class="token punctuation">.</span>completed <span class="token operator">||</span>
          status <span class="token operator">==</span> AnimationStatus<span class="token punctuation">.</span>dismissed<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">if</span> <span class="token punctuation">(</span>isForward<span class="token punctuation">)</span> <span class="token punctuation">{</span>
          _animationController<span class="token punctuation">.</span><span class="token function">reverse</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
          _animationController<span class="token punctuation">.</span><span class="token function">forward</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>
      <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>status <span class="token operator">==</span> AnimationStatus<span class="token punctuation">.</span>reverse<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        isForward <span class="token operator">=</span> <span class="token boolean">false</span><span class="token punctuation">;</span>
      <span class="token punctuation">}</span>
    <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    _animationController<span class="token punctuation">.</span><span class="token function">forward</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>

  <span class="token metadata symbol">@override</span>
  <span class="token keyword">void</span> <span class="token function">dispose</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    _animationController<span class="token punctuation">.</span><span class="token function">dispose</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token keyword">super</span><span class="token punctuation">.</span><span class="token function">dispose</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>

  <span class="token metadata symbol">@override</span>
  Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token function">SingleChildScrollView</span><span class="token punctuation">(</span>
      child<span class="token punctuation">:</span> <span class="token function">Center</span><span class="token punctuation">(</span>
        child<span class="token punctuation">:</span> <span class="token function">Column</span><span class="token punctuation">(</span>
          crossAxisAlignment<span class="token punctuation">:</span> CrossAxisAlignment<span class="token punctuation">.</span>center<span class="token punctuation">,</span>
          children<span class="token punctuation">:</span> <span class="token operator">&lt;</span>Widget<span class="token operator">&gt;</span><span class="token punctuation">[</span>
            <span class="token function">AnimatedBuilder</span><span class="token punctuation">(</span>
              animation<span class="token punctuation">:</span> _animationController<span class="token punctuation">,</span>
              builder<span class="token punctuation">:</span> <span class="token punctuation">(</span>BuildContext context<span class="token punctuation">,</span> Widget child<span class="token punctuation">)</span> <span class="token punctuation">{</span>
                <span class="token keyword">return</span> <span class="token function">Padding</span><span class="token punctuation">(</span>
                  padding<span class="token punctuation">:</span> <span class="token keyword">const</span> EdgeInsets<span class="token punctuation">.</span><span class="token function">symmetric</span><span class="token punctuation">(</span>vertical<span class="token punctuation">:</span> <span class="token number">16.0</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
                  child<span class="token punctuation">:</span> <span class="token function">Column</span><span class="token punctuation">(</span>
                    children<span class="token punctuation">:</span> <span class="token operator">&lt;</span>Widget<span class="token operator">&gt;</span><span class="token punctuation">[</span>
                      <span class="token function">Wrap</span><span class="token punctuation">(</span>
                        spacing<span class="token punctuation">:</span> <span class="token number">10.0</span><span class="token punctuation">,</span>
                        runSpacing<span class="token punctuation">:</span> <span class="token number">16.0</span><span class="token punctuation">,</span>
                        children<span class="token punctuation">:</span> <span class="token operator">&lt;</span>Widget<span class="token operator">&gt;</span><span class="token punctuation">[</span>
                          <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                            <span class="token comment">// No gradient</span>
                            colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>blue<span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>blue<span class="token punctuation">]</span><span class="token punctuation">,</span>
                            radius<span class="token punctuation">:</span> <span class="token number">50.0</span><span class="token punctuation">,</span>
                            strokeWidth<span class="token punctuation">:</span> <span class="token number">3.0</span><span class="token punctuation">,</span>
                            value<span class="token punctuation">:</span> _animationController<span class="token punctuation">.</span>value<span class="token punctuation">,</span>
                          <span class="token punctuation">)</span><span class="token punctuation">,</span>
                          <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                            colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>red<span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>orange<span class="token punctuation">]</span><span class="token punctuation">,</span>
                            radius<span class="token punctuation">:</span> <span class="token number">50.0</span><span class="token punctuation">,</span>
                            strokeWidth<span class="token punctuation">:</span> <span class="token number">3.0</span><span class="token punctuation">,</span>
                            value<span class="token punctuation">:</span> _animationController<span class="token punctuation">.</span>value<span class="token punctuation">,</span>
                          <span class="token punctuation">)</span><span class="token punctuation">,</span>
                          <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                            colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>red<span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>orange<span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>red<span class="token punctuation">]</span><span class="token punctuation">,</span>
                            radius<span class="token punctuation">:</span> <span class="token number">50.0</span><span class="token punctuation">,</span>
                            strokeWidth<span class="token punctuation">:</span> <span class="token number">5.0</span><span class="token punctuation">,</span>
                            value<span class="token punctuation">:</span> _animationController<span class="token punctuation">.</span>value<span class="token punctuation">,</span>
                          <span class="token punctuation">)</span><span class="token punctuation">,</span>
                          <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                            colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>teal<span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>cyan<span class="token punctuation">]</span><span class="token punctuation">,</span>
                            radius<span class="token punctuation">:</span> <span class="token number">50.0</span><span class="token punctuation">,</span>
                            strokeWidth<span class="token punctuation">:</span> <span class="token number">5.0</span><span class="token punctuation">,</span>
                            strokeCapRound<span class="token punctuation">:</span> <span class="token boolean">true</span><span class="token punctuation">,</span>
                            value<span class="token punctuation">:</span> <span class="token function">CurvedAnimation</span><span class="token punctuation">(</span>
                                    parent<span class="token punctuation">:</span> _animationController<span class="token punctuation">,</span>
                                    curve<span class="token punctuation">:</span> Curves<span class="token punctuation">.</span>decelerate<span class="token punctuation">)</span>
                                <span class="token punctuation">.</span>value<span class="token punctuation">,</span>
                          <span class="token punctuation">)</span><span class="token punctuation">,</span>
                          <span class="token function">TurnBox</span><span class="token punctuation">(</span>
                            turns<span class="token punctuation">:</span> <span class="token number">1</span> <span class="token operator">/</span> <span class="token number">8</span><span class="token punctuation">,</span>
                            child<span class="token punctuation">:</span> <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                                colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>red<span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>orange<span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>red<span class="token punctuation">]</span><span class="token punctuation">,</span>
                                radius<span class="token punctuation">:</span> <span class="token number">50.0</span><span class="token punctuation">,</span>
                                strokeWidth<span class="token punctuation">:</span> <span class="token number">5.0</span><span class="token punctuation">,</span>
                                strokeCapRound<span class="token punctuation">:</span> <span class="token boolean">true</span><span class="token punctuation">,</span>
                                backgroundColor<span class="token punctuation">:</span> Colors<span class="token punctuation">.</span>red<span class="token punctuation">[</span><span class="token number">50</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
                                totalAngle<span class="token punctuation">:</span> <span class="token number">1.5</span> <span class="token operator">*</span> pi<span class="token punctuation">,</span>
                                value<span class="token punctuation">:</span> <span class="token function">CurvedAnimation</span><span class="token punctuation">(</span>
                                        parent<span class="token punctuation">:</span> _animationController<span class="token punctuation">,</span>
                                        curve<span class="token punctuation">:</span> Curves<span class="token punctuation">.</span>ease<span class="token punctuation">)</span>
                                    <span class="token punctuation">.</span>value<span class="token punctuation">)</span><span class="token punctuation">,</span>
                          <span class="token punctuation">)</span><span class="token punctuation">,</span>
                          <span class="token function">RotatedBox</span><span class="token punctuation">(</span>
                            quarterTurns<span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">,</span>
                            child<span class="token punctuation">:</span> <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                                colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>blue<span class="token punctuation">[</span><span class="token number">700</span><span class="token punctuation">]</span><span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>blue<span class="token punctuation">[</span><span class="token number">200</span><span class="token punctuation">]</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
                                radius<span class="token punctuation">:</span> <span class="token number">50.0</span><span class="token punctuation">,</span>
                                strokeWidth<span class="token punctuation">:</span> <span class="token number">3.0</span><span class="token punctuation">,</span>
                                strokeCapRound<span class="token punctuation">:</span> <span class="token boolean">true</span><span class="token punctuation">,</span>
                                backgroundColor<span class="token punctuation">:</span> Colors<span class="token punctuation">.</span>transparent<span class="token punctuation">,</span>
                                value<span class="token punctuation">:</span> _animationController<span class="token punctuation">.</span>value<span class="token punctuation">)</span><span class="token punctuation">,</span>
                          <span class="token punctuation">)</span><span class="token punctuation">,</span>
                          <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                            colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>
                              Colors<span class="token punctuation">.</span>red<span class="token punctuation">,</span>
                              Colors<span class="token punctuation">.</span>amber<span class="token punctuation">,</span>
                              Colors<span class="token punctuation">.</span>cyan<span class="token punctuation">,</span>
                              Colors<span class="token punctuation">.</span>green<span class="token punctuation">[</span><span class="token number">200</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
                              Colors<span class="token punctuation">.</span>blue<span class="token punctuation">,</span>
                              Colors<span class="token punctuation">.</span>red
                            <span class="token punctuation">]</span><span class="token punctuation">,</span>
                            radius<span class="token punctuation">:</span> <span class="token number">50.0</span><span class="token punctuation">,</span>
                            strokeWidth<span class="token punctuation">:</span> <span class="token number">5.0</span><span class="token punctuation">,</span>
                            strokeCapRound<span class="token punctuation">:</span> <span class="token boolean">true</span><span class="token punctuation">,</span>
                            value<span class="token punctuation">:</span> _animationController<span class="token punctuation">.</span>value<span class="token punctuation">,</span>
                          <span class="token punctuation">)</span><span class="token punctuation">,</span>
                        <span class="token punctuation">]</span><span class="token punctuation">,</span>
                      <span class="token punctuation">)</span><span class="token punctuation">,</span>
                      <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                        colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>blue<span class="token punctuation">[</span><span class="token number">700</span><span class="token punctuation">]</span><span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>blue<span class="token punctuation">[</span><span class="token number">200</span><span class="token punctuation">]</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
                        radius<span class="token punctuation">:</span> <span class="token number">100.0</span><span class="token punctuation">,</span>
                        strokeWidth<span class="token punctuation">:</span> <span class="token number">20.0</span><span class="token punctuation">,</span>
                        value<span class="token punctuation">:</span> _animationController<span class="token punctuation">.</span>value<span class="token punctuation">,</span>
                      <span class="token punctuation">)</span><span class="token punctuation">,</span>

                      <span class="token function">Padding</span><span class="token punctuation">(</span>
                        padding<span class="token punctuation">:</span> <span class="token keyword">const</span> EdgeInsets<span class="token punctuation">.</span><span class="token function">symmetric</span><span class="token punctuation">(</span>vertical<span class="token punctuation">:</span> <span class="token number">16.0</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
                        child<span class="token punctuation">:</span> <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                          colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>blue<span class="token punctuation">[</span><span class="token number">700</span><span class="token punctuation">]</span><span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>blue<span class="token punctuation">[</span><span class="token number">300</span><span class="token punctuation">]</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
                          radius<span class="token punctuation">:</span> <span class="token number">100.0</span><span class="token punctuation">,</span>
                          strokeWidth<span class="token punctuation">:</span> <span class="token number">20.0</span><span class="token punctuation">,</span>
                          value<span class="token punctuation">:</span> _animationController<span class="token punctuation">.</span>value<span class="token punctuation">,</span>
                          strokeCapRound<span class="token punctuation">:</span> <span class="token boolean">true</span><span class="token punctuation">,</span>
                        <span class="token punctuation">)</span><span class="token punctuation">,</span>
                      <span class="token punctuation">)</span><span class="token punctuation">,</span>
                      <span class="token comment">//&#x526A;&#x88C1;&#x534A;&#x5706;</span>
                      <span class="token function">ClipRect</span><span class="token punctuation">(</span>
                        child<span class="token punctuation">:</span> <span class="token function">Align</span><span class="token punctuation">(</span>
                          alignment<span class="token punctuation">:</span> Alignment<span class="token punctuation">.</span>topCenter<span class="token punctuation">,</span>
                          heightFactor<span class="token punctuation">:</span> <span class="token number">.5</span><span class="token punctuation">,</span>
                          child<span class="token punctuation">:</span> <span class="token function">Padding</span><span class="token punctuation">(</span>
                            padding<span class="token punctuation">:</span> <span class="token keyword">const</span> EdgeInsets<span class="token punctuation">.</span><span class="token function">only</span><span class="token punctuation">(</span>bottom<span class="token punctuation">:</span> <span class="token number">8.0</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
                            child<span class="token punctuation">:</span> <span class="token function">SizedBox</span><span class="token punctuation">(</span>
                              <span class="token comment">//width: 100.0,</span>
                              child<span class="token punctuation">:</span> <span class="token function">TurnBox</span><span class="token punctuation">(</span>
                                turns<span class="token punctuation">:</span> <span class="token number">.75</span><span class="token punctuation">,</span>
                                child<span class="token punctuation">:</span> <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                                  colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>teal<span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>cyan<span class="token punctuation">[</span><span class="token number">500</span><span class="token punctuation">]</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
                                  radius<span class="token punctuation">:</span> <span class="token number">100.0</span><span class="token punctuation">,</span>
                                  strokeWidth<span class="token punctuation">:</span> <span class="token number">8.0</span><span class="token punctuation">,</span>
                                  value<span class="token punctuation">:</span> _animationController<span class="token punctuation">.</span>value<span class="token punctuation">,</span>
                                  totalAngle<span class="token punctuation">:</span> pi<span class="token punctuation">,</span>
                                  strokeCapRound<span class="token punctuation">:</span> <span class="token boolean">true</span><span class="token punctuation">,</span>
                                <span class="token punctuation">)</span><span class="token punctuation">,</span>
                              <span class="token punctuation">)</span><span class="token punctuation">,</span>
                            <span class="token punctuation">)</span><span class="token punctuation">,</span>
                          <span class="token punctuation">)</span><span class="token punctuation">,</span>
                        <span class="token punctuation">)</span><span class="token punctuation">,</span>
                      <span class="token punctuation">)</span><span class="token punctuation">,</span>
                      <span class="token function">SizedBox</span><span class="token punctuation">(</span>
                        height<span class="token punctuation">:</span> <span class="token number">104.0</span><span class="token punctuation">,</span>
                        width<span class="token punctuation">:</span> <span class="token number">200.0</span><span class="token punctuation">,</span>
                        child<span class="token punctuation">:</span> <span class="token function">Stack</span><span class="token punctuation">(</span>
                          alignment<span class="token punctuation">:</span> Alignment<span class="token punctuation">.</span>center<span class="token punctuation">,</span>
                          children<span class="token punctuation">:</span> <span class="token operator">&lt;</span>Widget<span class="token operator">&gt;</span><span class="token punctuation">[</span>
                            <span class="token function">Positioned</span><span class="token punctuation">(</span>
                              height<span class="token punctuation">:</span> <span class="token number">200.0</span><span class="token punctuation">,</span>
                              top<span class="token punctuation">:</span> <span class="token number">.0</span><span class="token punctuation">,</span>
                              child<span class="token punctuation">:</span> <span class="token function">TurnBox</span><span class="token punctuation">(</span>
                                turns<span class="token punctuation">:</span> <span class="token number">.75</span><span class="token punctuation">,</span>
                                child<span class="token punctuation">:</span> <span class="token function">GradientCircularProgressIndicator</span><span class="token punctuation">(</span>
                                  colors<span class="token punctuation">:</span> <span class="token punctuation">[</span>Colors<span class="token punctuation">.</span>teal<span class="token punctuation">,</span> Colors<span class="token punctuation">.</span>cyan<span class="token punctuation">[</span><span class="token number">500</span><span class="token punctuation">]</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
                                  radius<span class="token punctuation">:</span> <span class="token number">100.0</span><span class="token punctuation">,</span>
                                  strokeWidth<span class="token punctuation">:</span> <span class="token number">8.0</span><span class="token punctuation">,</span>
                                  value<span class="token punctuation">:</span> _animationController<span class="token punctuation">.</span>value<span class="token punctuation">,</span>
                                  totalAngle<span class="token punctuation">:</span> pi<span class="token punctuation">,</span>
                                  strokeCapRound<span class="token punctuation">:</span> <span class="token boolean">true</span><span class="token punctuation">,</span>
                                <span class="token punctuation">)</span><span class="token punctuation">,</span>
                              <span class="token punctuation">)</span><span class="token punctuation">,</span>
                            <span class="token punctuation">)</span><span class="token punctuation">,</span>
                            <span class="token function">Padding</span><span class="token punctuation">(</span>
                              padding<span class="token punctuation">:</span> <span class="token keyword">const</span> EdgeInsets<span class="token punctuation">.</span><span class="token function">only</span><span class="token punctuation">(</span>top<span class="token punctuation">:</span> <span class="token number">10.0</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
                              child<span class="token punctuation">:</span> <span class="token function">Text</span><span class="token punctuation">(</span>
                                <span class="token string">&quot;${(_animationController.value * 100).toInt()}%&quot;</span><span class="token punctuation">,</span>
                                style<span class="token punctuation">:</span> <span class="token function">TextStyle</span><span class="token punctuation">(</span>
                                  fontSize<span class="token punctuation">:</span> <span class="token number">25.0</span><span class="token punctuation">,</span>
                                  color<span class="token punctuation">:</span> Colors<span class="token punctuation">.</span>blueGrey<span class="token punctuation">,</span>
                                <span class="token punctuation">)</span><span class="token punctuation">,</span>
                              <span class="token punctuation">)</span><span class="token punctuation">,</span>
                            <span class="token punctuation">)</span>
                          <span class="token punctuation">]</span><span class="token punctuation">,</span>
                        <span class="token punctuation">)</span><span class="token punctuation">,</span>
                      <span class="token punctuation">)</span><span class="token punctuation">,</span>
                    <span class="token punctuation">]</span><span class="token punctuation">,</span>
                  <span class="token punctuation">)</span><span class="token punctuation">,</span>
                <span class="token punctuation">)</span><span class="token punctuation">;</span>
              <span class="token punctuation">}</span><span class="token punctuation">,</span>
            <span class="token punctuation">)</span><span class="token punctuation">,</span>
          <span class="token punctuation">]</span><span class="token punctuation">,</span>
        <span class="token punctuation">)</span><span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<p>&#x600E;&#x4E48;&#x6837;&#xFF0C;&#x5F88;&#x70AB;&#x9177;&#x5427;&#xFF01;<code>GradientCircularProgressIndicator</code>&#x5DF2;&#x7ECF;&#x88AB;&#x6DFB;&#x52A0;&#x8FDB;&#x4E86;&#x7B14;&#x8005;&#x7EF4;&#x62A4;&#x7684;flukit&#x7EC4;&#x4EF6;&#x5E93;&#x4E2D;&#x4E86;&#xFF0C;&#x8BFB;&#x8005;&#x5982;&#x679C;&#x6709;&#x9700;&#x8981;&#xFF0C;&#x53EF;&#x4EE5;&#x76F4;&#x63A5;&#x4F9D;&#x8D56;flukit&#x5305;&#x3002;</p>

                                
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